Java EE Application Assembly and Deployment

A Java EE application is packaged into one or more standard units for
deployment to any Java EE platform-compliant system. Each unit contains:

A functional component or components (such as an enterprise
bean, JSP page, servlet, or applet)

An optional deployment descriptor that describes its content

Once a Java EE unit has been produced, it is ready to be deployed. Deployment
typically involves using a platform’s deployment tool to specify location-specific
information, such as a list of local users that can access it and the name
of the local database. Once deployed on a local platform, the application
is ready to run.